1. Field
The present disclosure relates to an electrode array, and more particularly, to an electrode array for analyzing electrical characteristics of a cell spheroid.
2. Description of the Related Art
Cell therapy is known as therapy for functional restoration of cells and tissues that involves cultivating living autogenic, allogeneic, or xenogeneic cells with modification to biological characteristics to obtain a cell therapy product, and injecting the resulting cell therapy product to replace old cells.
In cell therapy, there is a method of transplanting two-dimensionally cultured cells (for example, stem cells), but there are problems; two-dimensional (2D) cell culturing on a large scale is difficult and the probability of survival and an adhesion rate of transplanted cells is very low.
To solve the problems, the use of a so-called “cell spheroid” cultured in three dimensions (3D) as a cell therapy product has been proposed.
A cell spheroid is an assembly of multiple cells, for example, adult stem cells for transplantation, which forms aggregates in 3D.
To make a proper use of a cultured cell spheroid as a cell therapy product, an electrical characteristics analysis needs to be conducted to ascertain a type of cell spheroid, an extent of growth, and a state of synapse connection between cells.
For electrical characteristics analysis of two-dimensionally cultured cells (“2D cells”), a micro electrode array (MEA) system is known.
FIG. 1 is a conceptual diagram of an MEA system 1 according to a related art.
The MEA system 1 places 2D cells in a circular ring-type member 2′ formed on a substrate 2 and analyzes the electrical characteristics of the 2D cells.
In the central space of the ring-type member 2′, a plurality of pad-type electrodes are arranged in a grid, and the cultured 2D cells come into contact with the plurality of electrodes.
The MEA system 1 includes a stimulation system 4 electrically connected to the electrodes of the substrate 2 to provide electrical stimulation signals to the electrodes, a processing device 5 to analyze signals outputted from the electrodes, and a high speed charge coupled device (CCD) camera 3 to capture images of the cells. Using this construction, the electrical characteristics of the 2D cells may be analyzed.
However, when a 3D cell spheroid is placed on the micro electrode array of the MEA system according to the related art, signal acquisition is locally made only on a region where a contact between the cells and the electrodes is made due to a very small contact area between the electrodes and the cell spheroid.
In the case of the 3D cell spheroid, there is a need to ascertain a state of internal connection between each cell, but the micro electrode array according to the related art is inadequate for that.